Small pelagic fish reproductive strategies in upwelling systems: A natal homing evolutionary model to study environmental constraints

Authored by Christophe Lett, P Freon, C Mullon, T Brochier, F Colas, V Echevin, L A Cubillos, J Tam, M Chlaida

Date Published: 2009

DOI: 10.1016/j.pocean.2009.07.044

Sponsors: European Union

Platforms: No platforms listed

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

Although little is known about the individual-level mechanisms that influence small pelagic fish species' reproductive strategy, Mullon et al. {[}Mullon, C., Cury, P., Penven, P., 2002. Evolutionary individual-based model for the recruitment of anchovy (Engraulis capensis) in the southern Benguela. Canadian journal of Fisheries and Aquatic Sciences 59, 910-922] showed that the observed anchovy spawning patterns in the southern Benguela Current system off South Africa could be accurately reproduced by simulating a natal homing reproductive strategy, i.e. individuals spawning at their natal date and place. Here we used a similar method, i.e., an individual-based model of the natal homing reproductive strategy, and applied it to other upwelling systems: the northern Humboldt Current system off Peru, the southern Humboldt Current system off Chile and the central Canary Current system off Morocco. We investigated the spatial (horizontal and vertical) and seasonal spawning patterns that emerged after applying different environmental constraints in the model, and compared these to observed spawning patterns of sardine and anchovy in their respective systems. The selective environmental constraints tested were: (I) lethal temperature; (2) retention over the continental shelf-, and (3) avoidance of dispersive structures. Simulated horizontal spatial patterns and seasonal patterns compared reasonably well with field data, but vertical patterns in most cases did not. Similarly to what was found for the southern Benguela, temperature was a determinant constraint in the southern Humboldt. The shelf retention constraint led to selection of a particular spawning season during the period of minimum upwelling in all three of the upwelling regions considered, and to spatial patterns that matched observed anchovy spawning off Chile and sardine spawning off Morocco. The third constraint, avoidance of dispersive structures, led to the emergence of a spawning season during the period of maximum upwelling off Chile and Morocco, but not in Peru. The most accurate representation of observed spatio-temporal spawning patterns off Peru was achieved through a combination of shelf retention and non-dispersion constraints. (C) 2009 Elsevier Ltd. All rights reserved.

Tags

Marine fish Individual-based model Cod gadus-morhua California current system Anchoveta engraulis-ringens Sardine strangomera-bentincki 1997-1998 el-nino Upwelling region Eastern boundary Northwest africa